selector: update selector.Select to accept a slice of structs (#1764)

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ben-toogood 2020-06-30 15:51:26 +01:00 committed by GitHub
parent 6337c92cd0
commit b882ff3df9
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6 changed files with 38 additions and 43 deletions

1
go.sum
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@ -414,6 +414,7 @@ github.com/smartystreets/goconvey v0.0.0-20190330032615-68dc04aab96a/go.mod h1:s
github.com/soheilhy/cmux v0.1.4 h1:0HKaf1o97UwFjHH9o5XsHUOF+tqmdA7KEzXLpiyaw0E= github.com/soheilhy/cmux v0.1.4 h1:0HKaf1o97UwFjHH9o5XsHUOF+tqmdA7KEzXLpiyaw0E=
github.com/soheilhy/cmux v0.1.4/go.mod h1:IM3LyeVVIOuxMH7sFAkER9+bJ4dT7Ms6E4xg4kGIyLM= github.com/soheilhy/cmux v0.1.4/go.mod h1:IM3LyeVVIOuxMH7sFAkER9+bJ4dT7Ms6E4xg4kGIyLM=
github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME= github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
github.com/stretchr/objx v0.1.1 h1:2vfRuCMp5sSVIDSqO8oNnWJq7mPa6KVP3iPIwFBuy8A=
github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME= github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs= github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI= github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=

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@ -16,7 +16,7 @@ func (r *random) Options() Options {
return Options{} return Options{}
} }
func (r *random) Select(routes []*router.Route) (*router.Route, error) { func (r *random) Select(routes []router.Route) (*router.Route, error) {
// we can't select from an empty pool of routes // we can't select from an empty pool of routes
if len(routes) == 0 { if len(routes) == 0 {
return nil, ErrNoneAvailable return nil, ErrNoneAvailable
@ -24,14 +24,14 @@ func (r *random) Select(routes []*router.Route) (*router.Route, error) {
// if there is only one route provided we'll select it // if there is only one route provided we'll select it
if len(routes) == 1 { if len(routes) == 1 {
return routes[0], nil return &routes[0], nil
} }
// select a random route from the slice // select a random route from the slice
return routes[rand.Intn(len(routes)-1)], nil return &routes[rand.Intn(len(routes)-1)], nil
} }
func (r *random) Record(route *router.Route, err error) error { func (r *random) Record(route router.Route, err error) error {
return nil return nil
} }

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@ -38,7 +38,7 @@ func (r *roundrobin) Options() selector.Options {
return selector.Options{} return selector.Options{}
} }
func (r *roundrobin) Select(routes []*router.Route) (*router.Route, error) { func (r *roundrobin) Select(routes []router.Route) (*router.Route, error) {
if len(routes) == 0 { if len(routes) == 0 {
return nil, selector.ErrNoneAvailable return nil, selector.ErrNoneAvailable
} }
@ -51,33 +51,27 @@ func (r *roundrobin) Select(routes []*router.Route) (*router.Route, error) {
r.routes[hash] = time.Now() r.routes[hash] = time.Now()
} }
// calculate the route hashes once
hashes := make(map[*router.Route]uint64, len(routes))
for _, s := range routes {
hashes[s] = s.Hash()
}
// if a route hasn't yet been seen, prioritise it // if a route hasn't yet been seen, prioritise it
for srv, hash := range hashes { for _, route := range routes {
if _, ok := r.routes[hash]; !ok { if _, ok := r.routes[route.Hash()]; !ok {
setLastUsed(hash) setLastUsed(route.Hash())
return srv, nil return &route, nil
} }
} }
// sort the services by the time they were last used // sort the services by the time they were last used
sort.SliceStable(routes, func(i, j int) bool { sort.SliceStable(routes, func(i, j int) bool {
iLastSeen := r.routes[hashes[routes[i]]] iLastSeen := r.routes[routes[i].Hash()]
jLastSeen := r.routes[hashes[routes[j]]] jLastSeen := r.routes[routes[j].Hash()]
return iLastSeen.UnixNano() < jLastSeen.UnixNano() return iLastSeen.UnixNano() < jLastSeen.UnixNano()
}) })
// return the route which was last used // return the route which was last used
setLastUsed(hashes[routes[0]]) setLastUsed(routes[0].Hash())
return routes[0], nil return &routes[0], nil
} }
func (r *roundrobin) Record(srv *router.Route, err error) error { func (r *roundrobin) Record(srv router.Route, err error) error {
return nil return nil
} }

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@ -11,39 +11,39 @@ import (
func TestRoundRobin(t *testing.T) { func TestRoundRobin(t *testing.T) {
selector.Tests(t, NewSelector()) selector.Tests(t, NewSelector())
r1 := &router.Route{Service: "go.micro.service.foo", Address: "127.0.0.1:8000"} r1 := router.Route{Service: "go.micro.service.foo", Address: "127.0.0.1:8000"}
r2 := &router.Route{Service: "go.micro.service.foo", Address: "127.0.0.1:8001"} r2 := router.Route{Service: "go.micro.service.foo", Address: "127.0.0.1:8001"}
r3 := &router.Route{Service: "go.micro.service.foo", Address: "127.0.0.1:8002"} r3 := router.Route{Service: "go.micro.service.foo", Address: "127.0.0.1:8002"}
sel := NewSelector() sel := NewSelector()
// By passing r1 and r2 first, it forces a set sequence of (r1 => r2 => r3 => r1) // By passing r1 and r2 first, it forces a set sequence of (r1 => r2 => r3 => r1)
r, err := sel.Select([]*router.Route{r1}) r, err := sel.Select([]router.Route{r1})
assert.Nil(t, err, "Error should be nil") assert.Nil(t, err, "Error should be nil")
assert.Equal(t, r1, r, "Expected route to be r1") assert.Equal(t, r1, *r, "Expected route to be r1")
r, err = sel.Select([]*router.Route{r2}) r, err = sel.Select([]router.Route{r2})
assert.Nil(t, err, "Error should be nil") assert.Nil(t, err, "Error should be nil")
assert.Equal(t, r2, r, "Expected route to be r2") assert.Equal(t, r2, *r, "Expected route to be r2")
// Because r1 and r2 have been recently called, r3 should be chosen // Because r1 and r2 have been recently called, r3 should be chosen
r, err = sel.Select([]*router.Route{r1, r2, r3}) r, err = sel.Select([]router.Route{r1, r2, r3})
assert.Nil(t, err, "Error should be nil") assert.Nil(t, err, "Error should be nil")
assert.Equal(t, r3, r, "Expected route to be r3") assert.Equal(t, r3, *r, "Expected route to be r3")
// r1 was called longest ago, so it should be prioritised // r1 was called longest ago, so it should be prioritised
r, err = sel.Select([]*router.Route{r1, r2, r3}) r, err = sel.Select([]router.Route{r1, r2, r3})
assert.Nil(t, err, "Error should be nil") assert.Nil(t, err, "Error should be nil")
assert.Equal(t, r1, r, "Expected route to be r1") assert.Equal(t, r1, *r, "Expected route to be r1")
r, err = sel.Select([]*router.Route{r1, r2, r3}) r, err = sel.Select([]router.Route{r1, r2, r3})
assert.Nil(t, err, "Error should be nil") assert.Nil(t, err, "Error should be nil")
assert.Equal(t, r2, r, "Expected route to be r2") assert.Equal(t, r2, *r, "Expected route to be r2")
r, err = sel.Select([]*router.Route{r1, r2, r3}) r, err = sel.Select([]router.Route{r1, r2, r3})
assert.Nil(t, err, "Error should be nil") assert.Nil(t, err, "Error should be nil")
assert.Equal(t, r3, r, "Expected route to be r3") assert.Equal(t, r3, *r, "Expected route to be r3")
} }

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@ -21,9 +21,9 @@ type Selector interface {
// Options the selector is using // Options the selector is using
Options() Options Options() Options
// Select a route from the pool using the strategy // Select a route from the pool using the strategy
Select([]*router.Route) (*router.Route, error) Select([]router.Route) (*router.Route, error)
// Record the error returned from a route to inform future selection // Record the error returned from a route to inform future selection
Record(*router.Route, error) error Record(router.Route, error) error
// Close the selector // Close the selector
Close() error Close() error
// String returns the name of the selector // String returns the name of the selector

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@ -9,24 +9,24 @@ import (
// Tests runs all the tests against a selector to ensure the implementations are consistent // Tests runs all the tests against a selector to ensure the implementations are consistent
func Tests(t *testing.T, s Selector) { func Tests(t *testing.T, s Selector) {
r1 := &router.Route{Service: "go.micro.service.foo", Address: "127.0.0.1:8000"} r1 := router.Route{Service: "go.micro.service.foo", Address: "127.0.0.1:8000"}
r2 := &router.Route{Service: "go.micro.service.foo", Address: "127.0.0.1:8001"} r2 := router.Route{Service: "go.micro.service.foo", Address: "127.0.0.1:8001"}
t.Run("Select", func(t *testing.T) { t.Run("Select", func(t *testing.T) {
t.Run("NoRoutes", func(t *testing.T) { t.Run("NoRoutes", func(t *testing.T) {
srv, err := s.Select([]*router.Route{}) srv, err := s.Select([]router.Route{})
assert.Nil(t, srv, "Route should be nil") assert.Nil(t, srv, "Route should be nil")
assert.Equal(t, ErrNoneAvailable, err, "Expected error to be none available") assert.Equal(t, ErrNoneAvailable, err, "Expected error to be none available")
}) })
t.Run("OneRoute", func(t *testing.T) { t.Run("OneRoute", func(t *testing.T) {
srv, err := s.Select([]*router.Route{r1}) srv, err := s.Select([]router.Route{r1})
assert.Nil(t, err, "Error should be nil") assert.Nil(t, err, "Error should be nil")
assert.Equal(t, r1, srv, "Expected the route to be returned") assert.Equal(t, r1, *srv, "Expected the route to be returned")
}) })
t.Run("MultipleRoutes", func(t *testing.T) { t.Run("MultipleRoutes", func(t *testing.T) {
srv, err := s.Select([]*router.Route{r1, r2}) srv, err := s.Select([]router.Route{r1, r2})
assert.Nil(t, err, "Error should be nil") assert.Nil(t, err, "Error should be nil")
if srv.Address != r1.Address && srv.Address != r2.Address { if srv.Address != r1.Address && srv.Address != r2.Address {
t.Errorf("Expected the route to be one of the inputs") t.Errorf("Expected the route to be one of the inputs")